private static int availableCapacity(Buffer buffer) {
    return buffer.capacity() - buffer.limit();
  }

  /**
   * Flips the buffer output buffer so we can start reading bytes from it. If we are starting to
   * drain because there was overflow, and there aren't actually any characters to drain, then the
   * overflow must be due to a small output buffer.
   */
  private void startDraining(boolean overflow) {

      limiter.acquire(); // #5
    }
    stopwatch.sleepMillis(4250); // #6, back to cold state (warmup period + repay last acquire)
    for (int i = 0; i < 11; i++) {
      limiter.acquire(); // #7, showing off the warmup starting from totally cold
    }

    // make sure the areas (times) remain the same, while permits are different
    assertEvents(
        "R0.00, R1.38, R1.13, R0.88, R0.63, R0.50, R0.50, R0.50", // #1

  public abstract C previous(C value);

  /**
   * Returns a signed value indicating how many nested invocations of {@link #next} (if positive) or
   * {@link #previous} (if negative) are needed to reach {@code end} starting from {@code start}.
   * For example, if {@code end = next(next(next(start)))}, then {@code distance(start, end) == 3}
   * and {@code distance(end, start) == -3}. As well, {@code distance(a, a)} is always zero.
   *

  /**
   * Returns a view of a slice of this byte source that is at most {@code length} bytes long
   * starting at the given {@code offset}. If {@code offset} is greater than the size of this
   * source, the returned source will be empty. If {@code offset + length} is greater than the size
   * of this source, the returned source will contain the slice starting at {@code offset} and
   * ending at the end of this source.
   *

    ImmutableMap<Service, Long> startupTimes = serviceManager.startupTimes();
    assertThat(startupTimes).hasSize(2);
    assertThat(startupTimes.get(a)).isAtLeast(150);
    // Service b startup takes at least 353 millis, but starting the timer is delayed by at least
    // 150 milliseconds. so in a perfect world the timing would be 353-150=203ms, but since either
    // of our sleep calls can be arbitrarily delayed we should just assert that there is a time

  private static final ListenerCallQueue.Event<Listener> STARTING_EVENT =
      new ListenerCallQueue.Event<Listener>() {
        @Override
        public void call(Listener listener) {
          listener.starting();
        }

        @Override
        public String toString() {
          return "starting()";
        }
      };

  public void testStateOrdering() {
    // List every valid (direct) state transition.
    assertLessThan(NEW, STARTING);
    assertLessThan(NEW, TERMINATED);

    assertLessThan(STARTING, RUNNING);
    assertLessThan(STARTING, STOPPING);
    assertLessThan(STARTING, FAILED);

    assertLessThan(RUNNING, STOPPING);
    assertLessThan(RUNNING, FAILED);

    assertLessThan(STOPPING, FAILED);

    assertTrue(Arrays.equals(reference, target));
    assertTrue(Arrays.equals(reference, target));

    Object[] expectedArray1 = expectModify ? reference : starting;
    Object[] expectedArray2 = expectModify ? target : starting;
    assertTrue(Arrays.equals(expectedArray1, array1));
    assertTrue(Arrays.equals(expectedArray2, array2));
  }

  public void testPrependZeroElements() {

   */
  public int indexIn(CharSequence sequence) {
    return indexIn(sequence, 0);
  }

  /**
   * Returns the index of the first matching BMP character in a character sequence, starting from a
   * given position, or {@code -1} if no character matches after that position.
   *
   * <p>The default implementation iterates over the sequence in forward order, beginning at {@code

        assertThrows(
            TimeoutException.class, () -> service.startAsync().awaitRunning(1, MILLISECONDS));
    assertThat(e)
        .hasMessageThat()
        .isEqualTo("Timed out waiting for Foo [STARTING] to reach the RUNNING state.");
  }

  private class TestService extends AbstractScheduledService {
    CyclicBarrier runFirstBarrier = new CyclicBarrier(2);
    CyclicBarrier runSecondBarrier = new CyclicBarrier(2);